Movie Makers (Jan-Dec 1952)

28 JANUARY 1952 by A. E. Gillings; Tale of a Kite, by John Soulsby, and What Shall We Film?, by Michael and Margaret Davies. An award of £5 goes to each of the winners. Lancaster For the second half of the current year the Amateur Cinema Club of Lancaster, in Pennsylvania, will offer a series of weekly instructional sessions covering all phases of film making, from basic camera technique through scripting, direction and lighting. A tour of local television studios acquainted members with the film uses and needs of the new industry. The club is currently conducting a membership drive. Persons interested in the activities of this group should write to Fred J. Ruof, jr., ACL, 619 South Queen Street, Lancaster, Pa. Synchronizing sound on tape [Continued from page 19] ing these principles to his tape recorder, Mr. Dow selected as his strobe disc mount the hub or end of the tape capstan because of its fixed revolutions per minute. However, in so doing, he was faced with the problem that the capstan was shielded by and did not extend above the surface of the front tape guard. The essentially simple way in which he solved this problem is best made clear in the illustrations. From Fig. 1 (showing the general operating setup ) , we progress to Figs. 2 and 3 in which, in side and front closeups, the positioning of the strobe disc is shown in relation to other parts of the machine. However, examination of these pictures also will indicate that some method has been devised (1) for getting at the capstan head, and (2) attaching a disc to it which clears the surface of the tape guard. The beginnings of this method are suggested in Fig. 4. First, by removing the front tape guard the capstan was exposed. It was now possible to measure its diameter (about % inch) and to measure also the height necessary for an extension to the capstan which would clear the strobe disc above the re-installed tape guard. (On the Revere this dimension also proved to be about y2 inch.) Mr. Dow then fashioned this extension shaft out of wood, formed his 18 segment disc (IV2 inches in diameter) nut of cardboard and attached it to the wooden shaft with a simple screw (see Figs. 4 and 5). Attachment of this combined unit (extension shaft and disc) to the metal capstan (see Fig. 5) was effected will: Black Magic cement. There remained now only I lie re installation of the front tape guard. But, as will be seen in Fig. 6, before this could be done it was necessary to cut away a notch providing clearance for the capstan extension. On Mr. Dow's model of the Revere, this guard is diecast metal and quite thin, so that it was (he says) an easy matter to cut out the clearance hole with a jigsaw. With the guard repositioned, the installation may now become permanent. So much for Mr. Dow's amazingly easy and thoroughly operable adaptation of the Levett synchro-sound system to a tape recorder. We are grateful to him both for his data and his excellent illustrations. OTHER MOUNTING METHODS However, thinking that Mr. Levett would be especially interested in this development of his system, we submitted the Dow material to him for study. It is to him that we are indebted for these added suggestions. In connection with mounting the strobe disc, for example, Mr. Levett comments: "There are, of course, various ways by which the strobe disc could be attached to the capstan. The top of the capstan can be drilled and tapped so that the disc and capstan extension can be attached with a metal screw. Or it would be possible to drill the capstan for three small holes and to fit the capstan extension with three small pins which would fit these holes. With this setup, the capstan extension and disc could be merely pushed on and pulled off. "For it is not necessary that this unit be a permanent installation — if one is reluctant to cut a notch in the front tape guard. In this connection I found that on current models of this Revere recorder the tape guards are now shaped from a plastic material which certainly could be sawed with even greater ease than the metal cited by Mr. Dow. "On the other hand, these newer models have the housing units over the capstan attached merely by a push-fit, so that the front cover can be lifted off instantly at any time. Further, the machine will operate satisfactorily with .the housing removed, so that it would not be necessary to have the strobe disc installation permanent and therefore not necessary to cut away part of the housing." SOURCES OF ERROR Estimating the possible accuracy of this synchro system when applied to a tape recording, Mr. Levett also comments interestingly as follows: "The only possible source of error in this system — and I believe it to be a minor one — is the question of shrinkage or stretching of the tape, and of slippage as the tape passes the capstan. That is the reason, incidentally, why professional recording studios use a system whereby they can manually correct for either slippage or shrinkage or stretching. "For example, some outfits use a capstan that is actually a sprocket, and the tape is perforated. J. A. Maurer uses a different system which consists of a recorder having two heads; one takes the music and narration while the second head impresses on the tape, simultaneously with the narration and music, a sine wave. On playback, two heads pick off the two different tracks, the sine wave being projected visibly and being held stationary by manual control. This is, of course, quite complicated equipment-wise and probably beyond the average amateur. STROBE PATTERN ON TAPE "However, a system which is just as effective as the Maurer method, and which can be handled by any amateur, is to mark the tape. In this case a small white dot, or a white vertical line, is printed on the tape every inch or so throughout the length of the tape, the distance between the points being predetermined for the frame speed desired and the rate of tape travel. The flicker from the projector then lights up the dots or vertical stripes (which are simply another form of strobe pattern) directly on the tape. Thus, any slippage, shrinkage or stretching has no adverse effect on synchronization. "It is my belief that a printing outfit, such as is used to print labels and things of that general type, could be used to put the proper impressions on the tape. However, I feel sure that most any amateur could make his own device for printing on the tape, which is certainly what I will do if and when I try out this procedure." How one amateur edits [Continued from page 13] down, stick it on a small rewind post, and feed it over to a 400 foot reel opposite. You can even pass it through the viewer again, if there is any need for trimming or polishing. (In this connection it may be noted in Fig. 1 that the small rewinds are canted in toward the viewer to give smooth travel. ) With this sequence completed on the 400 footer, the whole thing is finally fed to the big reels in the rear. And now for a few of those dimensions which I promised you. Let's take the sorting rack first. Its overall measurements are 25V2 inches in widtl and 24V2 inches in height. The num bered shelves are of 1 inch lumber, with a clearance of 4 inches between each, and they have been tilted down at the rear by ^ inch so that gravity keeps the reels in place. The reel-sepa